The Administrative and Food Composition Core for this Program Project provides a group of resources, services and leadership skills that are essential for the conduct of the component Projects. These consist of: 1. Coordination and Support Dr. Willett will provide the overall leadership for the Projects conducted within this Program. He meets with all Project leaders and co-investigators every two weeks as a group to review issues related to the overall Program and the progress of the specific Projects, including priorities for data collection and analysis. This meeting provides for intellectual interchange and cross-fertilization among the investigators. Dr. Rimm will assist Dr. Willett in overseeing the day-to-day operations of the Program Project. The Core staff will provide administrative assistance and secretarial support for the individual Projects and facilitate communications among them. 2. The Semi-quantitative Food Frequency Questionnaire Analysis System This questionnaire and its companion food composition database and nutrient analysis system are basic resources that are used in all of the component Projects, as well as by many other investigators within and outside our institution. The Core will support a Senior Dietitian with responsibility for developing and maintaining the food composition database. 3. Computing Facilities This Core will provide access to the computer hardware and extensive software resources used for data management and analysis by all of the component Projects. This computer facility, including 10 servers with approximately four gigabytes of memory, is located at the neighboring Channing Laboratory and is coordinated with the Nurses' Health Study and Nurses' Health Study II. Through this Core, the many activities within the overall Program Project are coordinated to generate a high level of scientific synergy that would not be provided by isolated research projects. Further, great efficiencies are obtained by the shared and coordinated use of common resources for dietary assessment and data processing that have been developed and refined over the last two decades.